When corrugated packing sheets are used in operations such as rectification, absorption, extraction and the like, gas rises through corrugated channels, while liquid flows downwardly through surfaces of the packing sheets and forms films thereon, thereby mass transfer is completed by counterflow contact between gas and liquid. The corrugated packing sheets have their own crests and troughs and, liquid flows downwardly mainly along the troughs. By this way, thick films are formed on the troughs and, the crests are in an exposed state, thus resulting in un-uniform distribution of liquid in column. When liquid is presented in troughs, then entire liquid channels inside the column will be kept unchanged for a long time, hence leading to unfavorable influence on vapor-liquid mass transfer and adversely influencing separation effects of the column.
To overcome the above-mentioned problems and improve separation efficiency of the corrugated packing sheet, the present laboratory (Tianjin Branch of State Key Laboratory of Chemical Engineering) firstly developed a “structured packing sheet with diversion windows and its structured packing (Chinese Patent Application No. 200810151274.5 has been filed for the subject matter)”. In this technical scheme, diversion windows are formed in both crests and troughs of the corrugated packing and, the directions of the diversion windows are opposite to the crests or troughs. When liquid flows downwardly, liquid at the troughs flows around the diversion windows and finally arrives at the back portion of the packing. So, the flow state can be reformed, which makes the vapor-liquid mass transfer more effective. To obtain better separation effects and lower the pressure drop, further improvements are made to the packing with diversion windows by the present laboratory. For example, in Chinese Patent Application No. 200910068166.6, square grooves are defined in the packing sheet. In Utility Model No. 200920307714.1, cosine flow-conducting baffles are added. In Chinese Patent Application No. 201010530832.6, both perforations and windows are formed. In Chinese Patent Application No. 201010577155.3, eccentric windows are formed. All above-mentioned novel packings have their individual features.